docs: def _initialize_encryption(self, options):
          # type: (Descriptor, blobxfer.models.options.Upload) -> None
          """Download is resume capable
          :param Descriptor self: this
          :param blobxfer.models.options.Upload options: upload options
          """
          if (options.rsa_public_key is not None and self.local_path.size > 0 and
                  (self._ase.mode == blobxfer.models.azure.StorageModes.Block or
                   self._ase.mode == blobxfer.models.azure.StorageModes.File)):
              em = blobxfer.models.crypto.EncryptionMetadata()
              em.create_new_metadata(options.rsa_public_key)
              self.current_iv = em.content_encryption_iv
              self._ase.encryption_metadata = em